The present invention relates to a golf club shaft. In general, the golf club shaft is subjected to torsion while it is swung. In this case, an amateur golfer who holds the golf club shaft can perceive the degree of the torsion thereof while swinging it if a base end side grip portion thereof has a proportion of more than 25 in the torsional angle thereof to the torsional angle of 100 of an end side portion thereof which is fitted with a club head. However, if the base end side grip portion of the golf club shaft is less than 25 in the proportion of the torsional angle thereof to that of the end side portion thereof which is fitted with the club head, a limited number of professional golfers alone who have cultivated fine senses for perceiving the torsion of the golf club shafts in their training are capable of feeling their torsional degrees. This is as experimentally confirmed.
On the other hand, in a conventional golf club shaft made of reinforced fiber or other similar material, if the end side portion thereof which is fitted with a club head is 1 in the torsional rigidity Td thereof, the base end side grip portion thereof is more than 6 in the torsional rigidity Tc thereof, as shown in FIG. 5.
For this reason, in the conventional golf club shaft, the base end side grip portion of the golf club shaft is 17 or below in the proportion of the torsional angle thereof to that of 100 of the end side portion thereof to which the club head is attached. Therefore, an amateur golfer can not feel the torsional degree of the conventional club shaft while swinging it.
Under the circumstances, when the conventional golf club shaft undergoes unusual torsion which can be caused by irregular swing thereof, an amateur golfer who holds this conventional golf club shaft is not allowed to remedy the unusual torsion thereof.
However, if the conventional golf club shaft is reduced in the entire torsional rigidity thereof as shown with the two-dot chain line in FIG. 5, the amateur golfer is able to perceive torsion thereof while swinging it, while on the other hand, reduction in the torsional rigidity of the entire conventional golf club shaft excessively increases torsion of the end side portion thereof to which the club head is attached, and this can not allow the club head to remain constant in the direction thereof when the golf club shaft is swung, thereby causing a disadvantage or problem in which the conventional golf club shaft can not achieve any shot precisely in the direction as intended.
It is therefore an object of the present invention to provide for a golf club shaft which allows an amateur golfer to perceive the torsional degree thereof while swinging it, thereby achieving a shot thereby precisely in the intended direction.